Navigation system

ABSTRACT

Disclosed are a navigation system and/or a point information display method and a program. The navigation system consists mainly of: a stream receiver that receives broadcast streams; a data decoder that samples a data signal from the received streams and decodes the data signal into character string information; a matching block that performs matching to compare a predetermined keyword, which is associated with position information specified in map information data, with stored keywords and searches a keyword consistent with the keyword contained in the character string information; a position information searching block that searches position information associated with the keyword contained in the character string information and detected to be consistent with a stored keyword by the matching block; and a display unit that displays the detected position information while superimposing it on a display image.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation Application of patentapplication Ser. No. 12/010,470, filed Jan. 25, 2008, which is aDivisional Application of patent application Ser. No. 10/376,590, filedMar. 3, 2003, which in turn claims priority from Japanese ApplicationNo. 2002-068124, filed Mar. 13, 2002, the entire content beingincorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a navigation system, or moreparticularly, to a navigation system capable of presenting pointinformation associated with data of broadcast contents and a map datadisplay method.

2. Description of the Related Art

Navigation systems can detect the position of an own vehicle and atraveling speed thereof in real time by utilizing the global positioningsystem (GPS). A map is displayed on a display unit according todigitized map data. A current position measured by the GPS, arecommended route to a destination along which a user is guided to thedestination, or the like is displayed while being superimposed on thedisplay map.

The navigation system can present marks, which represent variouslandmarks such as fast-food restaurants, convenience stores, familyrestaurants, and event halls, while superimposing them on a mapdisplayed on a display unit on the basis of point information(hereinafter the marks displayed on the display unit shall be calledlandmarks). As for display of the landmarks, what category should bedisplayed or not displayed can be designated by selecting a menu itemfrom any of hierarchically structured menus displayed on the displaydevice.

As mentioned above, landmarks can be superimposed on a map presented bya navigation system. In a conventional navigation system, landmarksexistent in a portion of a map displayed on the display unit are merelydisplayed based on point information.

Incidentally, on-vehicle equipment includes a broadcast receiver havingthe ability to receive programs broadcast from television or radiobroadcasting stations. A commercial message (CM) is inserted betweenbroadcast programs. Assume that a CM is broadcast while a user who maybe a driver or a passenger in a compartment is watching or listening toa program presented by the broadcast receiver.

For example, the CM is a CM concerning a fast-food restaurant. The usermay want to drop at the fast-food restaurant. In this case, the useruses the navigation system to search the nearest fast-foot restaurant onthe basis of a displayed region (current point). The user thendesignates the fast-food restaurant displayed as the result of thesearch, and searches a route to the fast-food restaurant by himself orherself.

As mentioned above, when a specific one is designated from amongdisplayed landmarks or a new landmark is searched, an action must beperformed on the navigation system. Consequently, the navigation systemmust be operated. It is a nuisance to operate the navigation system forsearch every time a user gets interested in a program or a CM that isbroadcast from time to time. Besides, it is dangerous to operate thenavigation system during driving.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide anavigation system enabling a user to visually grasp the position of astore or the like in association with the contents of a CM or a programreceived by a broadcast receiver.

Another object of the present invention is to provide a means for addinga value to information of stores or the like registered as one oflandmarks.

Through a discussion on the foregoing underlying problems, a presentinventor concentrated his attention on a stream that is employed indigital television broadcast whose service will start in the nearfuture. According to the present invention, a specific keyword containedin any of streams representing a CM or a program triggers offpresentation of the position of a broadcast store or the like by anavigation system.

In order to accomplish the above objects, one aspect of the presentinvention resides in a navigation system having the components describedbelow. That is to say, the navigation system consists mainly of: astream receiving means for receiving broadcast streams; a data decodingmeans for sampling a data signal from the received streams and decodingthe data signal into character string information; a keyword recordingmeans in which predetermined keywords associated with positioninformation specified in map information data are stored; a matchingmeans for performing matching to compare character string informationwith each of the keywords stored in the keyword recording means andsearching a keyword consistent with a keyword contained in the characterstring information; a position information searching means for searchingposition information associated with the keyword contained in thecharacter string information and detected to be consistent with arecorded keyword by the matching means; and a display means fordisplaying the detected position information while superimposing it on adisplay image. When it says that position information is displayed whilebeing superimposed on a display image, it means that the positioninformation may be not only superimposed on the display image but alsoallowed to flicker or colored so that it can be distinguished from theother position information.

When position information associated with a keyword is contained in aportion of a map image displayed on the display means, a mark indicatingthe position information is displayed on the map image.

The navigation system further includes a display control means forchanging the scale for a portion of a map image displayed on the displaymeans when position information associated with a keyword is notcontained in the portion of the map image.

In another aspect, the navigation system includes a navigation means forsearching the route to the position indicated with a mark displayed onthe display means or for guiding a user to the position.

In the navigation system having the foregoing components, if a receivedstream contains a keyword, position information associated with thekeyword, that is, a mark is displayed on the display screen. A receivedstream is searched for a keyword in real time (stream reception). If thekeyword is contained in the stream, the keyword triggers off display ofassociated position information. Namely, the navigation system presentsposition information in association with a received stream.

In still another aspect, the present invention resides in a navigationsystem having the components described below. That is to say, thenavigation system consists mainly of: an information processing unit forsampling position information associated with contents acquiredexternally; and a display unit that displays the sampled positioninformation in association with the received contents whilesuperimposing it on a map image. A means for acquiring contentsexternally may be a contents receiving unit included in the navigationsystem. Otherwise, other equipment may receive contents and thenavigation system may receive the contents.

A memory in which position information is temporarily stored may beincluded. When position information cannot be displayed in associationwith contents, the position information is stored in the memory.Position information read from the memory is superimposed on a map imagedisplayed on the display unit. When position information is thus storedin the memory, even after contents are watched or listened to, positioninformation can be displayed.

In yet another aspect, the present invention resides in a pointinformation display method adaptable to a navigation system. That is tosay, the point information display method consists mainly of: a step ofreceiving broadcast contents and decoding information concerning thecontents; a step of judging whether a keyword association with pointinformation concerning a position on a map is contained in the decodedinformation; and a step of searching map information data for pointinformation associated with the keyword contained in the decodedinformation, and displaying the point information while superimposing iton the map.

In another aspect, the present invention resides in a program forcontrolling an information processor that displays map information andpoint information. That is to say, the program allows the informationprocessor to perform: a process for receiving a broadcast radio wave,separating a predetermined signal from the other components of the radiowave, and decoding the predetermined signal; a process for searching thedecoded information for character string information consistent with akeyword stored in the information processor; and a process fordisplaying point information according to point information and positioninformation associated with the keyword while superimposing the pointinformation on a map image.

Other and further objects, features and advantages of the invention willappear more fully from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing the configuration of a navigationsystem in accordance with an embodiment of the present invention;

FIG. 2A and FIG. 2B show packets employed in digital televisionbroadcast and transmitted during digital television broadcast;

FIG. 3 shows a table recorded in a keyword dictionary employed in theembodiment;

FIG. 4A and FIG. 4B show an example of display on a display unitincluded in the navigation system in accordance with the embodiment;

FIG. 5 is a flowchart describing a flow of processing steps according towhich the navigation system of the embodiment presents a landmark inassociation with a CM or a program; and

FIG. 6 is a flowchart describing a flow of processing steps according towhich display and non-display of a landmark is switched in associationwith a CM or a program.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the appended drawings that show an embodiment of thepresent invention, the present invention will be described below.

The number of users of digital television broadcast dependent on asatellite broadcasting service is increasing. Moreover, provision of adigital television broadcast service based on ground waves is going tostart. A packet employed in digital television broadcast and transmittedfrom a broadcasting station has a data field. The packet employed indigital television broadcast will be described later. According to thepresent embodiment, a navigation system uses information recorded in thedata field to present a landmark in association with the contents of abroadcast CM or program (with a keyword contained in the CM or programas a trigger).

FIG. 1 is a block diagram showing the configuration of the navigationsystem in accordance with the present embodiment.

As illustrated, the navigation system consists mainly of: a display unit41 such as a liquid crystal display or any other monitor on which a mapand various kinds of information are displayed responsively to amanipulation performed on an operating unit such as a remote controlleror a control panel; a loudspeaker 42 for generating voice or the like soas to give a guidance; a control unit 10 for controlling the wholenavigation system; and a position measuring unit 20 for measuring theposition of a vehicle. As mentioned above, the navigation system inaccordance with the present embodiment includes a broadcast receiverunit 30 that receives a digital television signal. Hereinafter, a casewhere the broadcast receiver unit 30 is integrated with the navigationsystem will be described. As long as data can be transmitted to thecontrol unit 10, the navigation system and the broadcast receiver unit30 may be independent of each other.

The control unit 10 consists mainly of: a navigation block 11 having aROM in which a program describing a control sequence for controlling thewhole navigation system is stored and a CPU that performs arithmeticoperations according to the program stored in the ROM; a RAM (memory) 12serving as an internal memory for assisting in performing actionsdescribed in the program, and holding data of a map and others; adisplay controller 13 for controlling data to be displayed on thedisplay unit 41; an audio controller 14 for controlling audio data thatis generated by the loudspeaker 42 in order to give a guidance or thelike; a disk drive 15 capable of reading map information from arecording disk such as a CD-ROM or DVD-ROM in which map information dataconcerning a predetermined wide area is stored; and a storage controller16 for controlling the disk drive 15.

Moreover, the control unit 10 included in the navigation system inaccordance with the present embodiment includes: a matching block 18composed of a ROM in which a matching program that will be describedlater is stored and a CPU that performs arithmetic operations accordingto the program; and a keyword dictionary 17 in which keywords used formatching are recorded.

The position measuring unit 20 includes: a GPS antenna 21 through whicha signal originated from any of GPS satellites is received; a GPSposition measuring block 22 that measures a position according to asignal received through the GPS antenna 21; a vehicle speed sensor 23for detecting the vehicle speed of a vehicle in which the navigationsystem is mounted; a gyro sensor 24 for detecting a rotationaldisplacement made by the vehicle; and a measured position correctingblock 25 for correcting the result of position measurement performed bythe GPS position measuring unit 22 according to a value produced by thegyro sensor 24. In the navigation system, displaying the position of avehicle and giving a guidance are performed based on a value provided bythe measured position correcting block 25.

The navigation system in accordance with the present embodiment includesthe broadcast receiver unit 30 capable of receiving a digital televisionsignal. The broadcast receiver unit 30 includes: a digital broadcastreceiver 31 for receiving a radio wave (packet) from a broadcastingstation; a demultiplexer 32 for separating a video signal, an audiosignal, and a data signal, which constitute a multiplexed signal, fromone another and providing the separated signals; a data decoder 33 fordecoding the data signal and transmitting the resultant signal to thecontrol unit 10; a video decoder 34 for decoding the video signal anddisplaying an image on the display unit 41 according to the resultantsignal; and an audio decoder 35 for decoding the audio signal andgenerating sounds from the loudspeaker 42 according to the resultantsignal. The demultiplexer 32 separates the video signal, audio signal,and data signal from one another while referencing time stampsindicating time instants at which the signals are encoded. The timebases for the video signal and audio signal respectively aresynchronized with each other, so that output units can reproduce animage and sounds according to the video and audio signals at propertimings. The time base for the data signal accompanying the video andaudio signals is also synchronized with the time bases for the video andaudio signals during matching. The timing of processing data can bematched with the timing of reproducing the image and sounds.

FIG. 2A and FIG. 2B show packets employed in digital televisionbroadcast and transmitted during digital television broadcast.

As shown in FIG. 2A, transport streams (TS) include a video transportstream (TS) that represents a video signal, an audio transport stream(TS) that represents an audio signal, and a data transport stream (TS)that represents a data signal. Video TSs, audio TSs, or data TSs aregathered up to produce an independent TS packet. The independent TSpackets of video TSs, audio TSs, and data TSs respectively aremultiplexed with the time bases therefor matched with one another,whereby a multiplexed TS packet composed of the video TSs, audio TSs anddata TSs is produced.

In a data TS field of the multiplexed TS packet, information concerningthe contents of a video TS and an audio TS is described in the form of,for example, an ASCII character string. The data TS contains not onlyinformation of, for example, a fast-food restaurant or a conveniencestore but also information of a store name (or a company name or a groupname) such as “◯◯◯ Burger” or “ΔΔΔStore.” Moreover, the data TS maycontain information that is displayed as a superimposed caption or aproduct name. From information contained in the data TS, it can bejudged to what a currently broadcast CM or program is related. If thedata TS contains specific character string information (keyword), thecharacter string information may trigger off display of a landmark inassociation with a CM or program.

FIG. 2B shows the structure of a multiplexed TS packet composed ofindependent TS packets shown in FIG. 2A. As shown in FIG. 2B, aplurality of video TSs constitutes an elementary stream (ES) that is aseries of streams having an unrestricted length. A packed elementarystream (PES) packet header is appended to the start of the ES, whereby aPES packet is produced. Likewise, a PES packet is produced from audioTSs or data TSs. The PES packet composed of independent TSs such asvideo TSs, audio TSs, or data TSs is transmitted while being split intoan adaptation field having a leading packet header and a payload. Thus,one TS packet is produced. A packet identifier (PID) or the like isdefined in the packet header. Based on the PID, a kind of TS packet canbe identified. Recorded in the adaptation field is information ofprogram_clock_reference (PCR) that is referenced in order to match timebases with one another during decoding. Based on the PCR information,the timing of reproducing each TS packet can be controlled. A pluralityof TS packets is gathered up to produce a multiplexed TS that looks likeone stream having a plurality of programs incorporated therein. The thusproduced multiplexed TS is utilized for digital television broadcast. Asmentioned above, the multiplexed TSs employed in digital televisionbroadcast are transmitted as a multiplexed TS packet composed of videostreams, audio streams, and data streams.

FIG. 3 shows a table recorded in the keyword dictionary 17 included inthe present embodiment. As illustrated, recorded in a keyword field in akeyword table 50 are not only a category of business but also a concretestore name. For example, “◯◯◯ Burger” and “*** Kitchen” that are namesof fast-food restaurants, “Family Restaurant ♦♦♦” and “□□□'S” that arenames of family restaurants, and “ΔΔΔ Store” and “xxx Mart” that arenames of convenience stores are recorded.

According to the present invention, matching is performed in order tocompare character string information, which is contained in a data TSrepresenting a CM or program received by the digital broadcast receiver31, with each of the keywords recorded in the keyword table 50 containedin the keyword dictionary 17.

For example, assume that a CM concerning “◯◯◯ Burger” is broadcast. Thedigital broadcast receiver 31 receives the CM, and the demultiplexer 32separates different kinds of signal components from one another so as tothus decode the received signal. A data TS (character stringinformation) decoded by the data decoder 33 is transferred to the RAM 12included in the control unit 10 and held in the RAM 12. Assume that thedata TS contains a character string “◯◯◯ Burger.” The matching block 18judges whether the character string information in the data TS held inthe RAM 12 contains a keyword consistent with any of the keywordsrecorded in the keyword table 50.

Through matching, it is judged that the data TS representing the CMcontains a character string “◯◯◯ Burger” consistent with a recordedkeyword. Position information and a landmark concerning “◯◯◯ Burger” arecontained in map information. The navigation block 11 searches the mapinformation for the data of the landmark (for the position information)so as to judge whether the information of “◯◯◯ Burger” is contained in aportion of the map information that can be displayed on the display unit41. The landmark for “◯◯◯ Burger” that can be displayed on the displayunit is displayed while being superimposed on a map displayed on thedisplay unit 41.

As mentioned above, when a keyword is specified in character stringinformation contained in a data TS, map information is searched for alandmark associated with the keyword. The landmark is then displayed onthe display unit 41. Through matching, a keyword contained in a streamrepresenting a CM triggers off real-time display of a landmarkassociated with the contents of the CM or program.

As mentioned above, the keyword table 50 that is prepared in advance isused to perform matching. Otherwise, the contents of a received data TSmay be analyzed to detect a keyword. The keyword may then be added tothe keyword table 50 so that the navigation system will learn thekeyword.

FIG. 4A and FIG. 4B show an example of display on the display unit 41included in the navigation system of the present embodiment.

As shown in FIG. 4A, normally, a recommended route 64 from anown-vehicle position 62 to a destination 63 is displayed in a displayarea 61 (in which a map image is displayed) on the display unit 41included in the navigation system.

When a digital television signal specifying character string informationconsistent with a character string recorded in the keyword table 50 isreceived during driving, the foregoing matching is carried out.Thereafter, as shown in FIG. 4B, a landmark 65 a contained in a portionof map information that can be displayed in the display area 61flickers. The landmark 65 a is kept displayed until a keyword containedin character string information makes a hit next.

A landmark 65 b and a landmark 65 c located near the own-vehicleposition 62 are associated with a keyword that has made a hit. However,since the landmarks are contained in a portion of map information thatfalls outside the display area 61, they are not displayed. Herein, thelandmarks associated with the keyword that has made a hit and containedin the portion of the map information that falls outside the displayarea 61 are not displayed. Alternatively, a landmark located at apredetermined distance or less from the own-vehicle position 62 may bedisplayed by changing the scale for the portion of the map informationthat is displayed in the display area 61.

If no landmark can be displayed in association with a CM or program inthe display area, nothing may be displayed. Otherwise, the displaycontroller 13 may change the scale for the portion of the mapinformation that is displayed in the display area 61 so that a landmarkcan be displayed.

The navigation block 11 selects a landmark located in a direction ofadvancement, in which the vehicle advances from the own-vehicle position62, on the basis of information acquired by the position measuring unit20. The position information concerning the selected nearest landmark isused to search a route. Thus, a user can be guided to the point of thenearest landmark without the necessity of changing the direction ofadvancement from the own-vehicle position 62. As mentioned above, akeyword contained in character string information triggers off displayof a landmark. Moreover, a user can perform manipulations so as tochange his/her destination from the initial destination 63 to the pointof the landmark 65 a, and can be informed of the route to the landmark65 a.

FIG. 5 is a flowchart describing a flow of processing steps according towhich the navigation system of the present embodiment presents alandmark in association with a CM or program.

The digital broadcast receiver 31 included in the broadcast receiverunit 30 receives a multiplexed TS packet broadcast as a digitaltelevision signal (step 501). The demultiplexer 32 separates TSs, whichconstitute the multiplexed TS packet, from one another (step 502). Amongthe separated TSs, a data TS is decoded by the data decoder 33 (step503). The data TS is then transferred to the control unit 10.

When the control unit 10 receives the data TS, the matching block 18performs matching (step 504). During the matching, it is judged whetherthe data TS contains a keyword that is consistent with any of thekeywords recorded in the (keyword table 50 in the) keyword dictionary 17(step 505).

If it is judged at step 505 that the data TS does not contain thekeyword, steps 501 to 505 are repeatedly performed on subsequentmultiplexed TS packets. If it is judged at step 505 that the data TScontains the keyword, a portion of a map to be displayed in the displayarea on the display unit 41 is searched for a landmark associated withthe keyword (step 506). If it is then judged whether the landmarkassociated with the keyword is found (step 507).

If it is judged at step 507 that the landmark is not found, steps 501 to507 are repeatedly performed on subsequently received data TSs. If it isjudged at step 505 that the landmark is found, the display controller 13displays the landmark at a predetermined position while superimposing iton the map displayed on the display unit 41 (step 508). A landmark to bedisplayed in association with a CM or program may be displayed toflicker or displayed in a color different from a color in which theother landmarks are displayed. In any case, the landmark is displayed tobe distinguishable from the other landmarks.

FIG. 5 describes an example of displaying a landmark all the timeaccording to a received data TS. FIG. 6 describes a flow of processingsteps for switching display and non-display of a landmark associatedwith a CM or program.

Steps 601 to 603 are identical to steps 501 to 503 described in FIG. 5.The description of the steps will therefore be omitted.

When the control unit 10 receives a data TS, the data TS is stored andheld in the RAM 12 (step 604). It is then judged whether the interlockof display of a landmark with digital television broadcast is designated(step 605). If it is judged at step 605 that the interlock with digitaltelevision broadcast is undesignated, steps 601 to 605 are repeatedlyperformed on subsequently received TS packets. Meanwhile, the receiveddata TSs are sequentially stored in the RAM 12. If it is judged at step605 that the interlock with digital television broadcast is designated,the data TS is read from the RAM 12 (step 606). Matching is performed onthe data TS.

Steps 607 to 611 succeeding the matching are identical to steps 504 to508 described in FIG. 5. The description of the steps will therefore beomitted.

The ability to perform matching on a data TS received by the digitalbroadcast receiver 31 has been described. The object of matching is notlimited to the data TS broadcast as a component of a digital televisionsignal. For example, if an audio TS can be sampled, the sampled audio TSmay be compared with the keyword dictionary 17 during matching.Consequently, a landmark associated with a keyword contained in theaudio TS can be displayed.

As mentioned above, the navigation system of the present embodimentincludes the keyword dictionary 17 in which keywords associated withlandmarks are recorded, and the matching block 18 that performs matchingso as to compare a received data TS with keywords. Since the navigationsystem includes these facilities, even if a data TS transmitted from abroadcasting station does not conform to a special format, a landmarkcan be searched through matching. Consequently, a landmark associatedwith a keyword that has made a hit can be displayed.

A user of the navigation system can discern information of a store orthe like broadcast during a CM or program without the necessity ofperforming special manipulations. Moreover, a landmark presented by thenavigation system is the nearest landmark located in a direction ofadvancement. The user is therefore encouraged to drop at the indicatedpoint.

A sponsor of a CM to be broadcast as a digital television signal doesnot merely broadcast the CM but appends a keyword to a data TS so thatthe keyword will trigger off display of a landmark. Thus, the sponsorcan appeal to users at a good timing. That is to say, when broadcast ofa CM is interlocked with display of a landmark, the landmark presentedby the navigation system has the value of an advertisement of a store orthe like.

Moreover, the navigation system of the present embodiment utilizes adata TS received by the digital broadcast receiver 31. Therefore,software capable of performing matching and displaying a landmark shouldmerely be provided. Consequently, an increase in the cost of manufacturestemming from addition of facilities can be suppressed.

Furthermore, since a landmark in map information recorded in a DVD-ROMor the like has the value of an advertisement, if advertisers who wantto register their store names or the like in the keyword dictionary 17at a charge are recruited, map information can be provided for users ata low cost.

As described so far, according to the present invention, there isprovided a navigation system enabling a user to visually grasp theposition of a store or the like in association with the contents of a CMor program received by a broadcast receiver.

Moreover, according to the present invention, information of a store orthe like registered as a landmark is added a value. Consequently, theusefulness of CMs can be improved and users' convenience can be ensured.

The foregoing invention has been described in terms of preferredembodiments. However, those skilled, in the art will recognize that manyvariations of such embodiments exist. Such variations are intended to bewithin the scope of the present invention and the appended claims.

FIG. 1

RADIO WAVE FROM BROADCASTING STATION

31: DIGITAL BROADCAST 32: DEMULTIPLEXER RECEIVER 34: VIDEO DECODER 35:AUDIO DECODER 33: DATA DECODER 17: KEYWORD DICTIONARY 11: NAVIGATIONBLOCK 18: MATCHING BLOCK 12: MEMORY 13: DISPLAY CONTROLLER 14: AUDIOCONTROLLER 16: STORAGE CONTROLLER 25: MEASURED POSITION CORRECTING BLOCK22: GPS POSITION MEASURING BLOCK 23: VEHICLE SPEED SENSOR 24: GYROSENSOR 41: DISPLAY UNIT

FIG. 2A

INDEPENDENT TS PACKET VIDEO TS VIDEO TS VIDEO TS AUDIO TS AUDIO TS AUDIOTS DATA TS DATA TS DATA TS

MULTIPLEXED TS PACKET

VIDEO TS VIDEO TS AUDIO TS DATA TS

FIG. 2B

TS PACKET TS PACKET TS PACKET TS PACKET TS PACKET

MULTIPLEXED TS PACKET

PACKET HEADER-ADAPTATION FIELD/PAYLOAD PES PACKET PES PACKET PES PACKETPES PACKET PES PACKET

PES PACKET

PES PACKET HEADER ELEMENTARY STREAM PES PACKET HEADER ELEMENTARY STREAMPES PACKET HEADER ELEMENTARY STREAM VIDEO TS VIDEO TS VIDEO TS AUDIO TSAUDIO TS AUDIO TS DATA TS DATA TS DATA TS

FIG. 3

KEYWORD ◯◯◯ BURGER *** KITCHEN HAMBURGER ΔΔΔ xxx DONUT ⊕⊕ FRIED CHICKENFAMILY RESTAURANT ♦♦♦ □□□'S ΔΔΔ STORE xxx MART □□□GAS STATION

FIG. 5

START S501: RECEIVE MULTIPLEXED TS PACKET BROADCAST AS DIGITALTELEVISION SIGNAL S502: SEPARATE TSS, WHICH CONSTITUTE MULTIPLEXED TSPACKET, FROM ONE ANOTHER S503: DECODE DATA TS S504: PERFORM MATCHING TOCOMPARE DATA TS WITH KEYWORD DICTIONARY S505: DOES DATA TS CONTAINKEYWORD? S506: SEARCH PORTION OF MAP INFORMATION TO BE DISPLAYED INDISPLAY AREA FOR LANDMARK S507: IS LANDMARK ASSOCIATED WITH KEYWORDFOUND? S508: DISPLAY LANDMARK WHILE SUPERIMPOSING IT ON MAP OR CHANGEDISPLAY END

FIG. 6

START S601: RECEIVE MULTIPLEXED TS PACKET BROADCAST AS DIGITALTELEVISION SIGNAL S602: SEPARATE TSS, WHICH CONSTITUTE MULTIPLEXED TSPACKET, FROM ONE ANOTHER S603: DECODE DATA TS S604: STORE DATA TS IN RAMS605: IS INTERLOCK WITH DIGITAL TELEVISION BROADCAST DESIGNATED? S606:READ DATA TS FROM RAM S607: PERFORM MATCHING TO COMPARE DATA TS WITHKEYWORD DICTIONARY S608: DOES DATA TS CONTAIN KEYWORD? S609: SEARCHPORTION OF MAP TO BE DISPLAYED IN DISPLAY AREA FOR LANDMARK S610: ISLANDMARK ASSOCIATED WITH KEYWORD FOUND?

S611: DISPLAY LANDMARK WHILE SUPERIMPOSING IT ON MAP OR CHANGE DISPLAY

1. A navigation method performed by a portable device, comprising:displaying map information for a predetermined area; receiving abroadcast stream having a commercial message; producing, from thebroadcast stream, a first content, including at least one of a videosignal and an audio signal, and a second content, including keywordinformation, the keyword information containing a plurality of keywords;recording a plurality of predetermined keywords associated with positioninformation, specified in the map information data; and matching saidkeyword information with the plurality of predetermined keywords forfinding at least one identified recorded keyword consistent with thekeyword information, and upon matching said keyword information:automatically determining a current navigational position of theportable device, automatically identifying at least one landmark,associated with the at least one identified recorded keyword, within amap image, and automatically displaying the current navigationalposition within the map image and the at least one identified landmarkwithin the displayed map image.
 2. The navigation method of claim 1,further comprising: changing the scale for the map image when thelandmark associated with the recorded keyword is not be within the mapimage, so that the landmark is displayed within the map image.
 3. Thenavigation method of claim 1, further comprising identifying timinginformation, contained in the broadcast stream, for synchronizing thefirst content with the keyword information; and associating the firstcontent with the landmark information with the keyword informationsharing the same timing information.
 4. The navigation method of claim1, further comprising: determining a route to the position of thelandmark and informing a user of the route.
 5. The navigation method ofclaim 1, wherein said broadcast content and keyword information arecontained in a data transport system and said broadcast content is acommercial message.
 6. The navigation method of claim 5, wherein thelandmark is associated with the commercial message.
 7. The navigationmethod of claim 1, wherein the landmark is displayed so that thelandmark is distinguished from other landmarks found within the mapimage.
 8. The navigation method of claim 1, wherein the map informationis recorded in a DVD-ROM.
 9. The navigation method of claim 1, whereinat least one keyword is associated with a plurality of landmarks. 10.The navigation method of claim 1, wherein at least one landmark isassociated with a plurality of recorded keywords.